Distance no object

"But how can your relationship ever move on, if you don't live together?" my friend asked me, when I told her I was irredeemably smitten with a man in Denmark, a country that doesn't even share my time-zone. At that point, I admitted I didn't know the answer. I just knew I wasn't prepared to give up on the love of my life just because the logistics were a hassle.

Both of us are divorced parents, so neither can uproot without causing turmoil, so the fact was that my new partner and I couldn't "move on" in the way my friend meant.

Conducting a committed relationship with somebody you can't be with when you want to demands a certain kind of maturity. It also demands an etiquette. Three rules quickly established themselves: the children must take priority, we must never spend longer than three weeks apart, and we must talk to each other daily. We've stuck to these rules, and developed a routine whereby, at least once a month, I find myself at Stansted airport, wondering how many other people in the check-in queue are like me: living a routine in one country punctuated by intense, rapturous spells of full-on romance in another. I suspect there are thousands of us all over the world thanking the god of market forces for low-cost airlines.

Within the first year, our relationship had evolved in a way neither of us could have predicted. I was still in London, and he was still in Copenhagen but our perception of the situation had shifted. The constrained nature of the relationship brought with it joys of its own. Acting like husband and wife isn't the only way to behave. Hell, why should it even be an ideal, when it's so much sexier to have all the passion of a honeymoon couple, combined with all the pleasures of an ever-deepening commitment? And why wring our hands over the fact that we each have our own independent lives, cultures and languages, when it's something to celebrate?

"The best lover to have lives five blocks away and leads a busy life," said the journalist Martha Gellhorn. She had a point. It began to strike us that, for every minor disadvantage, there is a huge advantage to our semi-detached life. We don't find ourselves indulging in domestic nit-picking, because there's no shared territory. In Copenhagen, we load the dishwasher his way, and in London, mine, though, it has to be said, dishwashers are not a priority when you have all that enforced celibacy to get out of your system. We are endlessly, passionately romantic about each other because familiarity doesn't get the chance to breed contempt. When our children meet, they get on amazingly well because nobody is trying to shoe-horn them into a live-together step-family.

But the fact remains that if we had the choice, we would start living together tomorrow, rather than in 10 years' time. Although living apart hasn't stopped us from moving on. On the contrary, our relationship has blossomed into the strongest, richest and most companionable that either of us has had. What's more, I suspect that we communicate far more, and far better, than a lot of married couples do because, when you have all the time in the world to talk, it's easy not to. As best friends and as lovers, we've found a way of being together while apart. Yes, there's plenty of longing. But there's never loneliness.

· Liz Jensen's novel, War Crimes For The Home, is published by Bloomsbury on July 8.